Articles | Volume 14, issue 9
Atmos. Chem. Phys., 14, 4679–4713, 2014

Special issue: The Modular Earth Submodel System (MESSy) (ACP/GMD inter-journal...

Atmos. Chem. Phys., 14, 4679–4713, 2014

Research article 13 May 2014

Research article | 13 May 2014

Intercomparison and evaluation of global aerosol microphysical properties among AeroCom models of a range of complexity

G. W. Mann1,2, K. S. Carslaw2, C. L. Reddington2, K. J. Pringle2,5, M. Schulz3, A. Asmi4, D. V. Spracklen2, D. A. Ridley2,6, M. T. Woodhouse2,25, L. A. Lee2, K. Zhang7,8, S. J. Ghan8, R. C. Easter8, X. Liu8,37, P. Stier9, Y. H. Lee10,13, P. J. Adams10, H. Tost5,32, J. Lelieveld5,12, S. E. Bauer11,13, K. Tsigaridis11,13, T. P. C. van Noije14, A. Strunk14, E. Vignati15, N. Bellouin16, M. Dalvi17, C. E. Johnson17, T. Bergman18, H. Kokkola18, K. von Salzen19, F. Yu20, G. Luo20, A. Petzold21,33, J. Heintzenberg22, A. Clarke23, J. A. Ogren24, J. Gras25, U. Baltensperger26, U. Kaminski27, S. G. Jennings28, C. D. O'Dowd28, R. M. Harrison29,34, D. C. S. Beddows29, M. Kulmala30, Y. Viisanen4, V. Ulevicius31, N. Mihalopoulos35, V. Zdimal36, M. Fiebig38, H.-C. Hansson39, E. Swietlicki40, and J. S. Henzing41 G. W. Mann et al.
  • 1National Centre for Atmospheric Science, University of Leeds, Leeds, UK
  • 2School of Earth and Environment, University of Leeds, Leeds, UK
  • 3Norwegian Meteorological Institute, Oslo, Norway
  • 4Helsinki University, Helsinki, Finland
  • 5Max Planck Institute for Chemistry, Mainz, Germany
  • 6Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
  • 7Max Planck Institute for Meteorology, Hamburg, Germany
  • 8Pacific Northwest National Laboratory, Richland, WA, USA
  • 9Department of Physics, University of Oxford, Oxford, UK
  • 10Civil & Environment Engineering, Carnegie Mellon University, Pittsburgh, PA, USA
  • 11Center for Climate Systems Research, Columbia University, New York, NY, USA
  • 12The Cyprus Institute, Nicosia, Cyprus
  • 13NASA Goddard Institute for Space Studies, New York, USA
  • 14Royal Netherlands Meteorological Institute (KNMI), De Bilt, the Netherlands
  • 15EU Joint Research Centre (JRC), Ispra, Italy
  • 16Department of Meteorology, University of Reading, Reading, UK
  • 17Met Office Hadley Centre, Exeter, UK
  • 18Finnish Meteorological Institute, Kuopio Unit, Kuopio, Finland
  • 19Canadian Centre for Climate Modelling and Analysis, Environment Canada, Canada
  • 20Department of Earth and Atmospheric Sciences, NY State University, Albany, USA
  • 21Institute of Atmospheric Physics, DLR, Oberpfaffenhofen, Germany
  • 22Leibniz Institute for Tropospheric Research, Leipzig, Germany
  • 23Department of Oceanography, University of Hawaii, Honolulu, HI, USA
  • 24Earth System Research Laboratory, NOAA, Boulder, Colorado, USA
  • 25CSIRO Marine and Atmospheric Research, Aspendale, Victoria, Australia
  • 26Paul Scherrer Institute, Villigen, Switzerland
  • 27Deutscher Wetterdienst (DWD), Germany
  • 28National University of Ireland Galway, Ireland
  • 29National Centre for Atmospheric Science, University of Birmingham, Birmingham, UK
  • 30Department of Physics, University of Helsinki, Helsinki, Finland
  • 31Center for Physical Sciences and Technology, Vilnius, Lithuania
  • 32Institute for Physics of the Atmosphere, Johannes Gutenberg University, Mainz, Germany
  • 33Forschungszentrum Juelich, IEK-8 Troposphere, Juelich, Germany
  • 34Department of Environmental Sciences, King Abdulaziz University, P.O. Box 80203, Jeddah, 21589, Saudi Arabia
  • 35Department of Chemistry, University of Crete, Heraklion, Greece
  • 36Institute of Chemical Process Fundamentals, Rozvojova, Prague, Czech Republic
  • 37Department of Atmospheric Science, University of WY, Laramie, Wyoming, USA
  • 38Department for Atmospheric and Climate Research, Norwegian Institute for Air Research (NILU), Norway
  • 39Department of Applied Environmental Science, Stockholm University, Sweden
  • 40Department of Physics, Lund University, Lund, Sweden
  • 41Netherlands Organisation for Applied Scientific Research (TNO), Utrecht, the Netherlands

Abstract. Many of the next generation of global climate models will include aerosol schemes which explicitly simulate the microphysical processes that determine the particle size distribution. These models enable aerosol optical properties and cloud condensation nuclei (CCN) concentrations to be determined by fundamental aerosol processes, which should lead to a more physically based simulation of aerosol direct and indirect radiative forcings. This study examines the global variation in particle size distribution simulated by 12 global aerosol microphysics models to quantify model diversity and to identify any common biases against observations. Evaluation against size distribution measurements from a new European network of aerosol supersites shows that the mean model agrees quite well with the observations at many sites on the annual mean, but there are some seasonal biases common to many sites. In particular, at many of these European sites, the accumulation mode number concentration is biased low during winter and Aitken mode concentrations tend to be overestimated in winter and underestimated in summer. At high northern latitudes, the models strongly underpredict Aitken and accumulation particle concentrations compared to the measurements, consistent with previous studies that have highlighted the poor performance of global aerosol models in the Arctic. In the marine boundary layer, the models capture the observed meridional variation in the size distribution, which is dominated by the Aitken mode at high latitudes, with an increasing concentration of accumulation particles with decreasing latitude. Considering vertical profiles, the models reproduce the observed peak in total particle concentrations in the upper troposphere due to new particle formation, although modelled peak concentrations tend to be biased high over Europe. Overall, the multi-model-mean data set simulates the global variation of the particle size distribution with a good degree of skill, suggesting that most of the individual global aerosol microphysics models are performing well, although the large model diversity indicates that some models are in poor agreement with the observations. Further work is required to better constrain size-resolved primary and secondary particle number sources, and an improved understanding of nucleation and growth (e.g. the role of nitrate and secondary organics) will improve the fidelity of simulated particle size distributions.

Final-revised paper